Tile levelling devices exist for aligning the external faces of adjacent tiles flush with one another during installation. One type of device uses a clip that is embedded in unset mortar below the adjacent tiles, with a frangible stem extending through the tile gap. A ratchet wedge is inserted into an aperture in the stem and positioned across the adjacent tiles until the tiles are gripped between the base and wedge. Another device uses a base that is embedded in unset mortar, and into which a stem is threaded until a disc connected to the stem clamps the tiles between the base and disc. In both cases after the mortar sets the stem is removed or severed from the base, leaving the base permanently embedded within the mortar.